4-Methylimidazole (1) is a heterocyclic organic chemical compound formed in the browning of certain foods through the Maillard reaction between carbohydrates and nitrogen compounds. It is found in roasted foods, grilled meats, coffee, and in types of caramel color produced with ammonia-based processes. Scheme 1 sets forth the likely reactions taking place during the caramel color production process.

Caramel color is one of the oldest and most widely-used food colorings, and is found in almost many commercially produced foods. Caramel color is manufactured by heating carbohydrates, alone or in the presence of acids, bases, and/or salts. There are four classes of caramel color, classified according to the reactants used in their manufacture, each with its own Class and INS, as listed in Table 1.
TABLE 1INSClassNo.NamePreparationUsesI150aPlain caramelNo ammonium or sulfiteWhiskey and othercompounds usedhigh proof alcoholsII150bCaustic sulfite caramelSulfite compounds but noCognac, sherry andammonium compoundssome vinegarsusedIII150cAmmonia caramel, baker'sAmmonium compounds butBeer, sauces, andcaramel, confectioner'sno sulfite compounds usedconfectionerycaramel, or beer caramelIV150dSulfite ammonia caramel,Both sulfite and ammoniumAcidic environmentsacid-proof caramel, or soft-compoundsincluding soft drinksdrink caramel
Caramel coloring of all types are considered safe and are approved by many leading regulatory agencies around the world, such as the European Food Safety Authority (USA), the US Food and Drug Administration (FDA), and the Joint FAO/WHO Expert Committee on Food Additives (JECFA).